It has long been recognized that the freshest, most aromatic and tasteful brewed coffee results when the raw or green coffee beans are roasted, ground and brewed as a coffee beverage as soon as possible. This is true because once roasted and ground, coffee quickly loses its essence, aroma and flavor.
The green unroasted coffee bean has a film-like covering which effectively excludes air and protects the beans against deterioration which affects flavor and aroma. This protecting film or covering on the coffee beans is removed during the roasting of the coffee beans as chaff, a flaked, dried film skin. The removal of this film covering leaves roasted beans exposed to undesirable deterioration. An unground roasted bean will retain much of its flavor and aroma for up to three months but then the flavor and aroma in the form of carbon dioxide evaporates from the bean. Ground beans exhibit a more rapid deterioration and once a vacuum packed can of ground coffee has been opened, significant flavor deterioration results in less than a week.
Additional flavor deterioration results because roasted coffee beans have an oily content and exposure to air materially alters the chemical makeup of these coffee oils resulting in a deterioration of flavor and aromatic attributes.
Small volume coffee roasters have been proposed heretofore but none of these prior proposals have found wide commercial acceptance. Such prior proposals for small volume coffee roasters are shown in U.S. Pat. Nos. 1,896,230, 1,985,604, 2,109,597, 2,154,963, 2,360,838, 2,413,687, 2,581,148, 2,906,193, 3,153,377 and 4,196,342. None of these prior art devices utilize the principal of the present invention which effectively and uniformly roasts green coffee beans to a desired roast degree.
One of the problems associated with the roasting of coffee beans is to insure that the temperature of the beans is carefully controlled to avoid elevating the temperature of the beans to an excessive degree. Coffee beans when elevated to too high a temperature exhibit a charcoaling effect in that the beans rapidly heat, ignite and glow much like heated charcoal. Another problem associated with roasting coffee beans is to insure an even and uniform roast of the beans so that the beans are uniformly roasted throughout. A still further problem in roasting coffee beans is to have an effective chaff removal. Chaff forms through the latter stages of a coffee roasting and is the residue of the protective film coating surrounding a green coffee bean.
Another problem associated with the roasting of coffee beans is to insure effective chaff removal. While the chaff content of coffee beans is less than 1% it is best to remove as much of the chaff as possible as chaff which remains with the ground coffee results in a brewed coffee beverage with a bitter taste.
Another problem associated with coffee roasting results when it is desired to blend coffee to achieve the benefit of a selection of various types of coffee beans for a particular desired coffee taste. When different coffee beans are involved, uniformity of roast presents problems as coffee beans are a commodity with variables similar to wine grape harvests. Thus the roasting of each batch must be carefully controlled. Because of differences in bean size, density, origin and other factors, commercial roasters are forced to roast each type of bean separately and then blend the roasted beans prior to grinding to achieve the desired coffee blend.
Accordingly, it is an object of the present invention to provide a simple yet effective apparatus to roast relatively small quantities of green coffee beans.
It is a further object of this invention to provide a coffee roasting apparatus for roasting small quantities of green coffee in an efficient and uniform manner to insure the obtainment of a flavorful and aromatic brewed coffee beverage.
A still further object of the present invention is to provide an efficient coffee roasting apparatus to impart a uniform roast to the coffee beans and to provide for a selection of a desired degree of roasting.
Yet another object of the present invention is to provide a coffee roasting apparatus with an effective and efficient chaff removal feature to insure an optimum brewed coffee taste.
A still further object of the present invention is to provide a coffee roaster in which a variety of different types of coffee beans, may be roasted at the same time.